noise_util.h (3009B)
1 /* 2 * Copyright (c) 2017, Alliance for Open Media. All rights reserved. 3 * 4 * This source code is subject to the terms of the BSD 2 Clause License and 5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License 6 * was not distributed with this source code in the LICENSE file, you can 7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open 8 * Media Patent License 1.0 was not distributed with this source code in the 9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent. 10 */ 11 12 #ifndef AOM_AOM_DSP_NOISE_UTIL_H_ 13 #define AOM_AOM_DSP_NOISE_UTIL_H_ 14 15 #ifdef __cplusplus 16 extern "C" { 17 #endif // __cplusplus 18 19 // aom_noise_tx_t is an abstraction of a transform that is used for denoising. 20 // It is meant to be lightweight and does hold the transformed data (as 21 // the user should not be manipulating the transformed data directly). 22 struct aom_noise_tx_t; 23 24 // Allocates and returns a aom_noise_tx_t useful for denoising the given 25 // block_size. The resulting aom_noise_tx_t should be free'd with 26 // aom_noise_tx_free. 27 struct aom_noise_tx_t *aom_noise_tx_malloc(int block_size); 28 void aom_noise_tx_free(struct aom_noise_tx_t *aom_noise_tx); 29 30 // Transforms the internal data and holds it in the aom_noise_tx's internal 31 // buffer. For compatibility with existing SIMD implementations, "data" must 32 // be 32-byte aligned. 33 void aom_noise_tx_forward(struct aom_noise_tx_t *aom_noise_tx, 34 const float *data); 35 36 // Filters aom_noise_tx's internal data using the provided noise power spectral 37 // density. The PSD must be at least block_size * block_size and should be 38 // populated with a constant or via estimates taken from 39 // aom_noise_tx_add_energy. 40 void aom_noise_tx_filter(struct aom_noise_tx_t *aom_noise_tx, const float *psd); 41 42 // Performs an inverse transform using the internal transform data. 43 // For compatibility with existing SIMD implementations, "data" must be 32-byte 44 // aligned. 45 void aom_noise_tx_inverse(struct aom_noise_tx_t *aom_noise_tx, float *data); 46 47 // Aggregates the power of the buffered transform data into the psd buffer. 48 void aom_noise_tx_add_energy(const struct aom_noise_tx_t *aom_noise_tx, 49 float *psd); 50 51 // Returns a default value suitable for denosing a transform of the given 52 // block_size. The noise "factor" determines the strength of the noise to 53 // be removed. A value of about 2.5 can be used for moderate denoising, 54 // where a value of 5.0 can be used for a high level of denoising. 55 float aom_noise_psd_get_default_value(int block_size, float factor); 56 57 // Computes normalized cross correlation of two vectors a and b of length n. 58 double aom_normalized_cross_correlation(const double *a, const double *b, 59 int n); 60 61 // Validates the correlated noise in the data buffer of size (w, h). 62 int aom_noise_data_validate(const double *data, int w, int h); 63 64 #ifdef __cplusplus 65 } // extern "C" 66 #endif // __cplusplus 67 68 #endif // AOM_AOM_DSP_NOISE_UTIL_H_